Struct StatementModeHandler 

pub struct StatementModeHandler { /* private fields */ }

Statement mode handler

In statement mode, connections are returned to the pool after every statement outside of an explicit transaction. This provides maximum connection sharing but with significant limitations.

Benefits:

• Maximum connection sharing
• Best for high-volume simple queries
• Good for read-heavy workloads with many clients

Limitations:

• CANNOT use server-side prepared statements (Parse/Bind/Execute)
• CANNOT use LISTEN/NOTIFY
• CANNOT rely on session variables
• CANNOT use temp tables effectively
• Must use simple query protocol

Use cases:

• Connection poolers like PgBouncer in statement mode
• High-throughput REST APIs with simple queries
• Serverless environments with many concurrent clients

Implementations

impl StatementModeHandler

pub fn new() -> Self

Create a new statement mode handler

pub fn with_autocommit(autocommit: bool) -> Self

Create with specific autocommit setting

pub fn create_lease( &self, connection: PooledConnection, client_id: ClientId, ) -> ConnectionLease

Create a lease for this mode

pub fn on_statement_complete( &self, lease: &mut ConnectionLease, sql: &str, ) -> LeaseAction

Process a statement and determine action

Returns the connection after every statement outside of explicit transaction.

pub fn on_transaction_end(&self, lease: &mut ConnectionLease) -> LeaseAction

Process transaction end signal from backend

pub fn should_release(&self, lease: &ConnectionLease) -> bool

Check if connection should be released

pub fn on_client_disconnect(&self, _lease: ConnectionLease) -> LeaseAction

Called when client disconnects

pub fn mode(&self) -> PoolingMode

Get the pooling mode

pub fn autocommit(&self) -> bool

Check if autocommit is enabled

pub fn tracks_prepared_statements(&self) -> bool

Prepared statements are not supported in statement mode

pub fn is_safe_query(&self, sql: &str) -> bool

Check if a query is safe for statement mode

Returns false for queries that require session state.

pub fn get_query_warning(&self, sql: &str) -> Option<&'static str>

Get warning if query is unsafe for statement mode

Trait Implementations

impl Default for StatementModeHandler

fn default() -> Self

Returns the “default value” for a type.